Reduce motorist delay Signals Pedestrians Access Management Conference September, 2004 Safety Intersection Improvements
Project Description FM 518 provides east-west mobility and access to many retail, commercial, residential and employment destinations. Commissioned by Houston-Galveston Area Council Supported by the Cities of Pearland, Friendswood, League City and Kemah, TxDOT, and Brazoria and Galveston Counties, and various private entities. 25.6 Miles, 4 lanes, TWLTL FM 518 intersects with four major north-south facilities such as US 288, SH 35, IH-45, and SH 146.
Study Process Twelve month study period Rational planning approach Public Involvement and Stakeholder meetings drove process
Current Corridor Conditions Corridor Sections LOS LOM SH 288 West Side to FM 865 (Cullen) E Moderate FM 865 (Cullen) CR 89 E Moderate CR 89 to Woody / Corrigan F Serious Woody / Corrigan to Halbert / McLean E Moderate Halbert / McLean to SH 35 / Main F Serious SH 35 / Main to Sherwood F Serious Sherwood to Woodcreek F Severe Woodcreek to Dixie Farm F Serious Dixie Farm to Williamsport A - D Tolerable Williamsport to Newport F Serious Newport to Interurban F Serious Interurban to SH 3 F Severe SH 3 to FM 270 / FM 2094 F Serious FM 270 / FM 2094 to South Shore F Severe South Shore to SH 146 A - D Tolerable
Corridor Goals and Objectives Improve safety Improve traffic flow Reduce motorist delay Identify short-term transportation improvements Assess long-term corridor needs
Access Management Tools Defined for Corridor
Identification of Operational Improvements This process involved not only modeling recommended physical improvements such as left turn and right turn lanes but also, included optimizing the intersection phasing, timing, and offsets. Over half (29) of the 58 signalized intersections along the corridor could be improved by a combination of adding right turn and/or left turn lanes and modifying signal timing.
One Additional Lane Improves Intersection Operation TYPICAL MINOR STREET LANE CONFIGURATIONS EXISTING (CREATES NEED FOR SPLIT-PHASING) ALTERNATIVE CONFIGURATIONS (DO NOT REQUIRE SPIT-PHASING)
Intersection Improvements Dedicated Left-Turn and Right- Turn Lanes Reduce Platoon Disruption and Enhance Signal Operations Shortening Signal Cycle Length Reduces Driver Delay
Silverlake Village/CR 94A Signal 3 Re-stripe NB and SB from left-only, left-orstraight, and right-only to left-only, straightonly, and right-only Change N-S signal sequence from splitphased to quad-left
Signal System Recommendation The remaining isolated intersections should be incorporated into closedloop systems. The timing of all of the systems should be optimized for current traffic.
Identification of Safety Improvements GIS used to identify crash locations (hazards) and document access connections.
Application of Raised Medians
Characteristics of a short-term raised median recommendation Intersection with a high crash rate (>10) Adjacent land use has good alternative access ways (driveway on cross street) Adjacent land use has adequate internal circulation The addition of the raised median has limited safety benefits, but does contribute aesthetically to a gateway feature.
Medium-Term Raised Median Recommendations Intersection with a medium crash rate (>5) Adjacent land use has alternative access ways (multiple driveways). Adjacent land use has opportunity to share access with another development
Driveway Consolidation Consolidation Recommendations Pearland - 103 Friendswood - 28 League City - 23 Total - 155 Opportunities to Consolidate Addition of right-turn lane Retrofit of property Sidewalk, drainage and sewer projects
Results Operational Safety Air Quality/Energy
Operational Benefits AM CORRIDOR TRAVEL TIME DELAY PM CORRIDOR DELAY COMPARISON Corridor Corridor 0 50 100 150 200 250 300 350 400 450 500 Hours of Delay 0 25 50 75 100 125 150 175 200 225 250 Hours of Delay Existing Condition Study Recommendations Existing Condition Study Recommendations
Driveways Related to Crashes Driveways and Crashes Existing Driveways 140 120 100 80 60 40 20 200 180 160 140 120 100 80 60 40 20 Crashes Per Analysis Segment Drivew ays Crashes 0 Pearland Friendswood League City Cities 0
Conflict Points After Raised Median 225 Conflict Points per Analysis Segment 2000 1500 1000 500 175 125 75 25 3 Year Crashes per Analysis Segment 0 Pearland Friendswood League City Kemah Total Conflict Points Proposed Conflict Points Crash Data -25
Air Quality Air Quality Benefits Pollutant % Reduced NOx = 37% VOC = 34% CO = 36% NO. City AADT For Different Segments Average AADT For Each City Average Peak Period Traffic For Each City Average Off-Peak Period Traffic For Each City Nox VOC CO Grams/Day 1 Pearland 24,000 2 " 26,000 3 " 28,000 4 " 22,000 5 " 26,000 6 " 37,000 7 " 30,000 8 Pearland 21,000 26,750 11,503 15,248 260,471 249,167 2,274,221 9 Friendswood 16,100 10 " 15,200 11 " 11,700 12 Friendswood 38,000 20,250 8,708 11,543 47,904 73,423 507,681 13 League City 38,000 15 League City 31,000 34,500 14,835 19,665 138,037 167,049 1,371,037 15 Kemah 16,500 16 " 9,100 17 Kemah 10,300 11,967 5,146 6,821 75,100 74,665 712,458 Corridor Total 399,900 23,367 10,048 13,319 521,512 564,304 4,865,397
Bicycle/Pedestrian Improvements
Future Corridor Recommendations
Comprehensive Plan Chapter 213.001 of the Texas Municipal Code Access Management Goal Statement Chapter 211.001 of the Texas Municipal Code Compliment Access Management Standards Zoning Ordinance Subdivision Ordinance Chapter 213.001 of the Texas Municipal Code Access Management Guidelines
Comprehensive Plans Establish general policy on access management. More specific statement: The FM 518 corridor is to be planned, designed and managed in accordance with the FM 518 Corridor Access Management Plan. Activity center strategies vs. strip development
Comprehensive Plans Use of parallel roads, side streets, and cross access easements connecting adjacent developments. Properties under the same ownership, consolidated for development, or part of phased development plans shall be considered one property for the purposes of access management. New residential subdivisions should include an internal street layout that connects to the streets of surrounding developments Commercial development should be encouraged to share common access connections as well as to provide a convenient system of interparcel circulation.
Thoroughfare Plans Establish street hierarchy Designate public right-of-way to mitigate impacts to the functional integrity of FM 518 and other major arterials. Limit direct access to major thoroughfares Establish access management policies guidelines
Land Use Recommendations Subdivision Regulations Establish cross and shared access provisions Establish minimum connection spacing requirements Minimum lot frontages Discourage residential access on major thoroughfares Zoning Discourage shallow strip development with no alternative access Overlay zones FM 518 Minimum Connection Spacing Posted Speed (mph) 30 35 40 45 50 Distance (ft) 200 250 305 360 425
Action Plan Agency Policy board approval of study H-GAC Adopt FM 518 Corridor Access Plan by ordinance Cities Secure funding for short-term intersection improvements H-GAC and TxDOT Implement intersection improvements TxDOT Implement system-wide signal retiming TxDOT and Cities Secure funding for median improvements H-GAC and TxDOT Implement median improvements TxDOT Coordinate with TxDOT for median aesthetics Cities Identify funding and implement pedestrian / bike improvements H-GAC, TxDOT, and Cities Program long range thoroughfare improvements Cities Update comprehensive plans and subdivision standards Cities